Telephone answering systems that automatically switch an incoming call to any of several telephone receivers and FAX machines are known. An example of such a system is disclosed in the above-mentioned U.S. Pat. No. 5,490,210.
Modern telephone systems send a caller ID signal, typically between the first and second ring signals, giving the telephone number from which a call is originating. The caller ID signal may be encoded by frequency shift keying (FSK) or dual tone multi frequency (DTMF) techniques.
The caller ID signal enables a telephone user who is receiving a call to determine the identity of the calling party before answering the phone. Typically this is done by observing the calling telephone number on an LCD screen on a control panel of the telephone. If the user does not wish to receive a call from the person whose number appears on the screen, the user may simply ignore the call.
Many telephone systems provide an option for special handling of calls received after business hours; this option may include automatically playing an outgoing message (OGM) to the caller to advise the caller of business hours during which a person may be available to take a call. The OGM may also invite the caller to leave a message which is thereupon stored. The OGM may also invite the caller to enter a predetermined code which rings directly through to connected telephone equipment associated with that code.